Dianthus Therapeutics (DNTH) insider sells 2,778 shares in 10b5-1 plan trades

Rhea-AI Filing Summary

Dianthus Therapeutics, Inc. (DNTH) director Simon Read reported an option exercise-and-sale on common stock. He exercised 2,778 stock options at an exercise price of $18.36 per share, acquiring 2,778 shares of common stock, and on the same date sold 2,778 shares at a weighted-average price of $117.55 per share. The option exercise left 19,445 options reported as outstanding after the transaction, with the option expiring on May 22, 2035. The transactions were effected pursuant to a Rule 10b5-1 trading plan adopted on May 8, 2026, and the option award vests in three equal annual installments, subject to continued service.

Insider Trade Summary 10b5-1

Exercise and Sale: 2,778 shares ($276K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Read Simon

Role Director

Sold 2,778 shs ($327K)

Approx. gross sale proceeds $327K

Approx. exercise cost $51K

Approx. pre-tax spread $276K

Type	Security	Shares	Price	Value
Exercise	Stock Option (Right to Buy) F1, F3	2,778	$0.00	$0.00
Exercise	Common Stock F1	2,778	$18.36	$51K
Sale	Common Stock F1, F2	2,778	$117.55	$327K

Holdings After Transaction: Stock Option (Right to Buy) — 19,445 shares (Direct); Common Stock — 0 shares (Direct)

Footnotes (3)

1. F1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted on May 8, 2026.
2. F2. The price reported above is a weighted average price. The shares were sold in multiple transactions at prices ranging from $117.01 to $117.66, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range.
3. F3. The shares of common stock underlying this stock option award vest as to one-third of the shares subject to the option on each of the first, second and third anniversaries of the date of grant, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

Key Figures

Options Exercised: 2,778 shares Option Exercise Price: $18.36 per share Shares Sold: 2,778 shares +4 more

7 metrics

Options Exercised 2,778 shares Stock options exercised into common stock on August 19, 2026

Option Exercise Price $18.36 per share Exercise price for stock options converted into 2,778 common shares

Shares Sold 2,778 shares Common stock sold following option exercise on August 19, 2026

Weighted-Average Sale Price $117.55 per share Weighted-average price for 2,778 common shares sold, within $117.01–$117.66 range

Remaining Options 19,445 options Total stock options reported as held after the partial exercise

Option Expiration Date May 22, 2035 Expiration of the stock option award from which 2,778 options were exercised

Rule 10b5-1 Plan Adoption Date May 8, 2026 Adoption date of trading plan governing the reported transactions

Key Terms

Rule 10b5-1 trading plan, weighted average price, stock option, vesting

4 terms

Rule 10b5-1 trading plan regulatory

"The reported transaction was effected pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average price financial

"The price reported above is a weighted average price"

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

stock option financial

"The shares of common stock underlying this stock option award vest"

A stock option is a contract that gives you the right to buy or sell a company's stock at a specific price within a certain time frame. People use them to potentially make money if the stock's price moves favorably or to protect against losses. It's like holding a coupon that can be used to buy or sell stock at a set price later on.

vesting financial

"underlying this stock option award vest as to one-third of the shares"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

FAQ

What insider transaction did Simon Read report for Dianthus Therapeutics (DNTH)?

Simon Read reported exercising 2,778 stock options at $18.36 per share and selling 2,778 common shares at a weighted-average price of $117.55 per share. These transactions occurred on August 19, 2026, as part of an exercise-and-sale sequence.

At what prices did the DNTH director exercise and sell shares in this Form 4?

The director exercised options at an exercise price of $18.36 per share and sold the resulting shares at a weighted-average price of $117.55 per share. Individual sales occurred between $117.01 and $117.66 per share, inclusive, across multiple transactions.

How many Dianthus Therapeutics (DNTH) options does Simon Read report remaining after this transaction?

After exercising part of his award, Simon Read reports 19,445 stock options remaining outstanding. These options relate to a grant expiring on May 22, 2035, with the underlying shares of common stock subject to a three-year vesting schedule.

Were Simon Read’s DNTH trades made under a Rule 10b5-1 plan?

Yes, the filing states the trades were effected under a Rule 10b5-1 trading plan adopted on May 8, 2026. Such pre-arranged plans allow insiders to schedule trades in advance, helping manage trading while limiting discretion over timing.

What is the vesting schedule of the DNTH stock options involved in this Form 4?

The options vest in three equal installments, with one-third of the shares vesting on each of the first, second, and third anniversaries of the grant date. Vesting is conditioned on the reporting person’s continued service to Dianthus Therapeutics on each vesting date.

What was the size of the DNTH share sale reported by Simon Read?

The reported sale covered 2,778 shares of common stock at a weighted-average price of $117.55 per share. The shares were sold through multiple trades within a price range of $117.01–$117.66 on the same trading day.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/19/2026 - 06:03 PM Accepted by SEC EDGAR 08/19/2026 - 06:02 PM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Read Simon

(Last) (First) (Middle)

C/O DIANTHUS THERAPEUTICS, INC.

7 TIMES SQUARE, 43RD FLOOR

(Street)

NEW YORK NEW YORK 10036

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Dianthus Therapeutics, Inc. /DE/ [ DNTH ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/19/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	08/19/2026		M(1)		2,778	A	$18.36	2,778	D
Common Stock	08/19/2026		S(1)		2,778	D	$117.55(2)	0	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	$18.36	08/19/2026		M(1)			2,778	(3)	05/22/2035	Common Stock	2,778	$0	19,445	D

Explanation of Responses:

1. The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted on May 8, 2026.

2. The price reported above is a weighted average price. The shares were sold in multiple transactions at prices ranging from $117.01 to $117.66, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range.

3. The shares of common stock underlying this stock option award vest as to one-third of the shares subject to the option on each of the first, second and third anniversaries of the date of grant, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

	/s/ Adam Veness, as attorney-in-fact for Simon Read	08/19/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)